The present invention relates to railroad freight cars including wells for carrying intermodal freight containers, and relates particularly to shortening existing container well cars to carry containers of a shorter length.
Many railroad freight cars were built over a period of several years, beginning in the 1980's, to be able to carry containers 48 feet long, as well as containers of the international standard 40-foot length, in container wells defined between deep side sills of the car bodies. Cars of this type are disclosed in U.S. Pat. No. 5,170,718, for example. Many of such 48-foot well cars were built as multi-unit cars, each usually having five container-well car units permanently coupled together. Recently, longer containers such as nominal 53-foot containers have largely replaced 48-foot containers. Since 48-foot well cars cannot accept the 53-foot containers, the cars with 48-foot wells began to be used largely for carrying 40-foot containers. Because of their greater length and weight, such cars are less efficient and more costly to use to carry 40-foot containers, and so owners of the cars have shortened many cars so that the container wells can still carry 40-foot containers, but don't have the extra eight-foot well length. The weight of material removed from the car bodies can be replaced by freight-earning lading without exceeding gross weight limitations. Also, more of the shortened cars can be included in a freight train without exceeding train length limitations.
It has been discovered that in many shortened container-well car units joints interconnecting the side sills and container corner support structures with the body bolsters and adjacent end portions of the car unites showed signs of failures and inability to sustain the loads resulting from carrying the lading for which the car units had been designed. Subsequent investigation revealed that gaps had remained unexpectedly unwelded between certain parts during the process of rejoining the ends of the well car units to shortened side sills, and a critical portion of the intended welded interconnection between end portions of the car units and the adjacent container well structures had not been able to be accomplished properly.
What is needed, then, is a joint structure and a method for shortening container-well units of railroad freight cars to result in strong, long-lasting, dependable, shortened container-well car units capable of carrying the full weight of lading for which the cars were originally designed, over a further lifetime of several years.